image credit: Eleni Katifori; image source; additional image

Why Leaves Aren't Trees - Sep 1, 2010

This is a lemon leaf that was wounded to interfere with its circulation. Note how the network of veins enabled nutrients to flow beyond the wound.

- Click on the image to see a similar experiment with a ginkgo leaf.
- To learn about the controversy over how these different vein structures developed, see Why Leaves Aren't Trees.

Image credit: Andrew Davidhazy; image source; Larger image

High speed photography - Aug 16, 2010

Look at the cavity behind the falling object that made this splash--you can learn how this cavity collapses if you check out From Physics Research.

- For more splash photos, see this page by Andrew Davidhazy, especially the splash sequence at the bottom.
- To learn about taking pictures that stop motion, see High speed photography.

Image credit: Malene Thyssen (Creative Commons); Image source; larger image

Ocean Waves - Aug 1, 2010

The side-view photo above shows how the back of a breaking wave spills over the front.

- This happens because as the wave enters more shallow water, its speed slows down, and the back of the wave overruns the front.
- If the reduction in depth happens quickly, the breaking wave creates a cylindrical cavity, as in the wave above.
- For more on ocean waves, see Ocean Waves and Ocean in Motion.

Image Credit: Denver International Airport; Image source; larger image

Tensile Structure - Jul 16, 2010

The roof of the Denver International Airport is a tensioned fabric structure designed by Horst Berger, a civil engineer famous for his large-scale fabric projects. The photo of the Denver airport above shows double-curved "minimal surfaces" that are characteristic of soap films (see From Physics Research).

- Visit Tensile Structure to learn more about this kind of construction.
- See this article from Structure magazine for information about Berger's career and numerous photos of his work.

image credit: Jim Gordon (Creative Commons); image source; larger image.

The Mystery of the Racing Rocks - Jul 1, 2010

What could cause rocks like this--of various sizes--to slide across the desert of Death Valley and leave these long tracks? The force of the wind... the force of moving ice sheets? To find out about these possibilities, visit The Mystery of the Racing Rocks and The Mystery of the Rocks.

Also check out The Sliding Tracks of Racetrack Playa for other explanations and more images.